Articular cartilage, found at the ends of articulating bone in the body, is typically composed of hyaline cartilage, which has many unique properties that allow it to function effectively as a smooth and lubricious load-bearing surface. When injured, however, hyaline cartilage cells are not typically replaced by new hyaline cartilage cells. Healing is dependent upon the occurrence of bleeding from the underlying bone and formation of scar or reparative cartilage called fibrocartilage. While similar, fibrocartilage does not possess the same unique aspects of native hyaline cartilage and tends to be far less durable.
In certain instances, an injury may not be limited to the cartilage, but may also extend into the bone which supports the cartilage.
In some cases, it may be desirable or necessary to repair the damaged articular cartilage and/or bone using an implant. In instances where only cartilage may be damaged, the implant should have a shape substantially corresponding to the articular cartilage proximate the area where the implant is to be placed in order to maximize the patient's comfort, minimize damage to surrounding areas, and maximize the functional life of the implant. In instances where bone is damaged, the implant may be increased in size to accommodate the damaged location.